Replacing the transmission output seal

[guitardad]

The bike in question is DW's 2004 R1150R Rockster, with almost 60k miles. It's been "weeping" a little oil which drips from the boot between swingarm and FD for a while, but the leak is worse over the last month. Looking up inside the swingarm, I can see that there's oil a long way up there. So I'm pretty sure the leak is from the transmission output shaft seal. Last couple of times the bike has been to the shop, we were told the trans output shaft seal would need to be replaced eventually. And with November upon us, if the bike sits for a while it's not such a big deal.

Now my Clymer says to split the transmission case to drive out the old seal from the inside. As does my R1100 factory manual (5-speed, I know, but still!). Has anyone ever replaced the output shaft seal without taking the transmission case apart? How, and how hard was it?

[41107]

if i remember there is ridge that the seal bottoms out against.So needs to come apart to drive in new seal.

[guitardad]

To answer my original question: Yes, one can replace the transmission output seal without disassembling the transmission. Here's how I did it....

The suggestion from Don at Bob's BMW was to use some dental picks to pry under the seal, and pull it out. That would avoid any risk of damaging the bearing by drilling into (and thru!) the seal. But every pick I have was too flimsy - it bent WAY before the seal moved. So I ended up drilling a couple of 1/16th holes in the seal, and putting in a couple of wood screws. One was too close to the edge, and just pulled out. I clamped vise-grips on the other, pried a little, and out she came!

http://home.comcast.net/~guitardad/trans/Web_old_seal.JPG

With the seal out, I could see the bearing was a sealed one. I wiped up all the oil in there, along with any metal bits from drilling.

http://home.comcast.net/~guitardad/trans/Web_bearing.JPG

Interestingly, the new seal is different from the old one. When DW went to get the part, it wasn't in stock, which is unusual for Bob's BMW. But they were purging their stock of the old part, and making sure we got the new one. New on the left, old on the right.

http://home.comcast.net/~guitardad/trans/Web_old_vs_new.JPG

I used a small PVC pipe fitting as a drift. It was the right size for the job, and the plastic is less likely to damage the seal. It's actually what I bought as a tool to install a swingarm bearing on my airhead - does that mean it's a BMW special tool? :D

http://home.comcast.net/~guitardad/trans/Web_drift.JPG

The easy part is tapping the new seal home. Job done!

http://home.comcast.net/~guitardad/trans/Web_new.JPG

All in all, not too bad a job. The hardest part was drilling the seal to put the screws in. The hole I thought was centered in the metal part of the seal was actually too close to the inner edge, and tore out. The one I thought was too close to the outer edge was just right. So that was an important lesson.

Coupla' other notes. I pulled the trans out to work on my workbench. The bike is overdue for a spline lube anyway (nearly 60k miles!) so I wasn't going to go to this point and not do the lube too. Working on the bench was much, much easier that it would have been to work on the trans in the bike.

Bike reassembly is underway!!!